“low-level,” some of this waste has high levels of radioactivity and could potentially be used to make an effective terrorism device.
RDD attacks could be carried out in several ways. Nonexplosive sources could be hidden in facilities frequented by large numbers of the public (e.g., sports stadiums, subway systems) or dispersed in building ventilation systems. Additionally, a radiation source could be combined with an explosive to disperse radioactive contamination over areas on the order of hundreds of square meters to a few square kilometers, depending on meteorological conditions. A radioactive waste shipment also could be attacked while in transit. Although such an attack probably would not disperse large quantities of radioactivity, it could cause public panic, especially if the attack took place in a highly populated urban area.
Detailed studies of RDDs suggest that few if any human deaths would be expected from dispersed radiation, although the explosion itself could cause casualties. The presence of dispersed radioactivity in the attacked area could, however, confound rescue efforts. The most severe effects on human health are produced if the material can be efficiently dispersed in respirable form. For optimum particulate sizes, inhaled material can remain lodged in the lungs, leading to either acute or chronic effects, depending on the amount and type of material respired. Although there are methods to construct an RDD to obtain good dispersion of inhalable particles, they require expert knowledge and access to university-level laboratory facilities.
The threat matrix presented in Table 2.1 and discussed in previous sections suggests that the United States faces several near-term (1-5 year) vulnerabilities to terrorist acts using nuclear and radiological dispersal weapons. Several potential vulnerabilities are described in this section.
At present, the United States has no evidence that a terrorist organization or nonnuclear state possesses stolen nuclear weapons or INDs. However, this situation could change rapidly over the near term if steps are not taken to better secure nuclear weapons and SNM, especially in Russia. In the future, efforts to develop INDs may involve virtual collaborations among groups of countries and terrorist organizations. These efforts will be harder to detect and interdict because the different materials, facilities, activities, and expertise will be spread across large and unconnected geographical areas. As noted above, the primary impediment to the success of IND development efforts is the availability of SNM, especially HEU. The first challenge, then, for the United States and its allies is to improve security for weapons and special nuclear material wherever they exist, but especially in Russia.